1. Technical Field
The present invention generally relates to electrical circuits and in particular to signal coupling between interconnect wires in electrical circuits.
2. Description of the Related Art
In module and system design of electrical circuits/devices, the performance of the system and the quality of propagating signals at the receiver end of the circuit is directly impacted by the losses through the signal path and the coupling noise in the system. As signaling speed increases, coupling noise becomes even more critical. For the high speed data link in a digital system, there is usually a driver at one end of one net of the high speed link and one or multiple receivers at the other end of the net. Traditionally, wiring rules call for a separation between driver and receiver channels to minimize the effects of near end crosstalk (NEXT) coupling into the victim line. There are two types of crosstalk: (1) forward crosstalk; and (2) backward crosstalk. The magnitude of forward crosstalk is proportional to the length of a net. Backward crosstalk is also proportional to the coupled length of two nets. Backward crosstalk saturates at the smaller of (a) two times the time of flight of the signal on a net and (b) the rising time of the aggressor signal.
In order to minimize the effects of near end crosstalk coupling, conventional system designs utilize an increased number of layers to escape the effects that may be caused by a particular channel. For example, conventional system designs utilize isolation layers to increase separation between drivers and receivers. The increase in the number of layers, however, leads to a corresponding increase in the implementation costs of the circuits/devices.